Interior solar energy collector with fluid-based heat transfer system

ABSTRACT

An interior solar energy collector system includes an interior heat exchanger unit for mounting on, or integral with, an interior surface of a roof or wall of a building. A heat transfer fluid system transfers collected heat from the interior heat exchanger to heat storage and heat disposal tanks from which the heat can be used or disposed as desired.

BACKGROUND

1. Technical Field of the Invention

The present invention is related to solar energy collection and use.

2. State of the Prior Art

Most solar collector systems are designed and implemented for maximizing or at least optimizing solar energy collection and efficiencies, which generally includes placing solar energy collection panels on roofs of buildings or on other structures that expose the solar collection panels directly to sunlight. Solar energy panels are available in a variety of technologies and configurations, several broad categories of which include: (i) Fluid-based heat exchangers that absorb solar energy from incident sunlight and heat a fluid, which is used for transport or storage of solar energy; and (ii) Solid state semiconductors that absorb solar energy from incident sunlight and convert the solar energy to electricity. For solar collection systems in which fluid-based heat exchangers are used for collecting the solar energy, various liquid storage and use apparatus and systems have been developed and studied, and some such systems have been available commercially for many years.

The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art and other examples of related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.

SUMMARY

The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be examples and illustrative, not limiting in scope. In various embodiments and implementations, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements and benefits.

An interior solar energy collector system for collecting and utilizing energy derived from solar radiation that is incident on an external surface of a roof or exterior wall of a building comprises a plurality of heat exchanger panels. Each panel comprises at least one tube that has a high thermal conductivity in thermally conductive relation to a sheet of high thermal conductivity material for conducting heat from the roof or exterior wall of the building to a heat transfer fluid that flows through the tubes of the panels. The tubes are connected to one or more inlet headers that distribute the heat transfer fluid to the panels where the fluid is heated by heat in the roof or exterior wall and one or more outlet headers that collect the heated heat transfer fluid from the panels for transport though a primary piping system to an insulated primary heat storage tank, sometimes referred to as a primary fluid storage tank. A primary heat transfer fluid pump in the first primary pipe system is configured for pumping fluid from the primary fluid storage tank to the inlet header, and heated fluid from the panels generally flows by gravity back to the primary heat storage tank although pumping could be used if desired or needed.

In addition to the example aspects, embodiments, and implementations described above, further aspects, embodiments, and implementations will become apparent to persons skilled in the art after becoming familiar with the drawings and study of the following descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate some, but not the only or exclusive, example embodiments and/or features of or relating to interior solar energy collection systems. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than limiting. In the drawings:

FIG. 1 is a diagrammatic view of an example interior solar energy collection system in a cross-sectional diagram of a building;

FIG. 2 is an isometric view of an example interior heat exchanger assembly that is usable as part of an interior solar energy collection system, the example interior heat exchanger assembly in this view being illustrated diagrammatically in phantom lines as mounted under the roof of building, a part of the roof being cut away to reveal a portion of the example interior heat exchanger assembly;

FIG. 3 is an enlarged elevation view of a lower portion of the example interior heat exchanger assembly as viewed from a perspective in the attic of the building in a plane 3-3 in FIGS. 1 and 2.

FIG. 4 is a logic flow diagram of an example operation of the example interior solar energy collection system in FIG. 1;

FIG. 5 is an isometric view of another example interior heat exchanger assembly, the interior heat exchanger assembly in this view being illustrated in phantom lines as mounted on the inside surface the roof, i.e., opposite the outside surface on which solar radiation is incident;

FIG. 6 is an enlarged perspective view of a part of the example interior heat exchanger assembly in FIG. 5 as viewed from a perspective in the interior of the building approximately in the plane 6-6 in FIG. 5; and

FIG. 6A is an enlarged view of the example joint in FIG. 6.

DETAILED DESCRIPTIONS OF EXAMPLE EMBODIMENTS

While most solar collector systems are designed and implemented for maximizing or at least optimizing solar energy collection and efficiencies, which generally includes placing solar energy collection panels on roofs of buildings or on other structures that expose the solar collection panels directly to sunlight, that kind of direct approach may not be practical for some buildings for a variety of reasons, e.g., deterioration of metals, plastics, and other materials in solar energy collection systems that are exposed directly to sunlight, rain, soil, leaves, and other natural and polluting elements in the atmosphere, potential hail damage, and the like. Roof-top solar collectors also present aesthetic challenges in building designs and may run afoul of some homeowner association covenants and architectural standards, and they may have to be cleaned periodically for optimal performance. In any event, the roofs and exterior walls of buildings themselves absorb substantial amounts of solar energy, which is often then lost, for example, by re-radiation as infrared radiation or by convection back into the atmosphere or into interior spaces of the buildings. To capture and use at least some of such solar energy, several example interior solar energy collection systems are illustrated in FIGS. 1-6. However, the illustrated embodiments are not the only or exclusive implementations of interior solar energy collection systems within the scope of the claims at the end of this description, so the claims are not intended to be limited in scope to these examples. Several examples of interior solar energy collector systems in this description are mounted on or adjacent to interior surfaces of roofs or exterior walls. The example heat exchanger systems for exterior walls described herein are substantially the same as the example heat exchanger systems for exterior walls. Therefore, to avoid cumbersome repetition, references to roofs in this description and in the claims are considered to include exterior walls unless explicitly stated otherwise.

In the example interior solar energy collection system 10 in FIG. 1, an interior solar energy collecting heat exchanger 12 is mounted on an interior surface S of the roof R of a building B to absorb heat in the roof R materials that is absorbed from incident solar energy on the roof R. For purposes of this description, interior surface means a surface that is inside the building B, as distinct from an exterior surface which would be outside of the building B. In this example interior solar collection system 10 in FIG. 1, the interior solar energy collecting heat exchanger 12 is in the attic portion A of the interior space I of the building B, but it could be in other portions of the interior space I, depending on the location of the interior surface S on which the interior solar energy collecting heat exchanger is mounted in a particular installation. The heat in the roof R that is absorbed from the incident solar radiation is conducted by the roof R materials to the solar energy collecting heat exchanger 12, which conducts the heat to a heat transfer fluid that is circulated through the interior solar energy collecting heat exchanger 12 as indicated by the flow arrows 19, 21, 22, 24 26, 28 and into a heat storage tank 18 where the heat is stored. In the example interior solar energy collection system 10 illustrated in FIG. 1, the heat transfer fluid is also used as a heat storage medium in 30 in the heat storage tank 18. However, the heat transfer fluid could be a separate fluid that flows through an optional heat transfer heat exchanger 32 as illustrated in phantom lines in FIG. 1 to transfer the heat from the interior solar energy collecting heat exchanger 12 into the heat storage medium 30 in the heat storage tank 18, if desired.

The heated heat storage medium 30 can then be used for various heating purposes in or around the building B. For example, a utility heat exchanger 34 in the heat storage medium 30 can be used to heat domestic water for various purposes, e.g., hot water faucets in lavatories, showers, sinks, and the like. In the example interior solar energy collection system 10 illustrated in FIG. 1, domestic water from a public water utility system, well, cistern, or other source (not shown) is flowed as indicated by flow arrows 36, 38 through the utility heat exchanger 34, where the domestic water is pre-heated before being flowed as indicated by flow arrow 42 to and through a more conventional hot water heater 40 (e.g., an electric powered or gas fired hot water heater). The conventional hot water heater 40 can be set to provide additional heat, if needed, to the domestic water before flowing as indicated by the flow arrow 44 to the hot water distribution system (not shown) that provides hot water to the hot water faucets or other hot water use points in the building B. The heat storage medium 30 can also be used to provide or supplement other heating systems in the building, e.g., radiant floor heating, hydronic baseboard heaters, steam radiant heating, driveway or sidewalk heating systems, and others (not shown), for example, by circulating the heat storage medium 30 from the heat storage tank 18 to and from such building heating systems as indicated by the flow arrows 46, 48 in FIG. 1.

The heat storage tank 18 may be insulated, e.g., with insulation 23, to help maintain available heat in the heat storage medium 30 from unnecessary dissipation and loss. A supplemental heater 50 can be provided, if desired, to add heat, if needed, to the heat storage medium 30 during periods when solar energy collected from the roof R by the interior solar energy collection heat exchanger 12 may be inadequate for the heating needs in the building B.

A roof temperature sensor 52 and a heat storage medium temperature sensor 54 can be provided, if desired, for use in controlling the circulation of the heat transfer fluid through the interior solar energy collecting heat exchanger 12 and the heat storage tank 18. For example, a pump 56 can be started when the roof temperature sensor 52 senses that the temperature of the roof R is greater than the temperature of the heat storage medium 30, as sensed by the heat storage medium temperature sensor 54, to draw the heat transfer fluid from the heat storage tank 18 and to pump the heat transfer fluid through the pipe 58 to the interior solar energy collecting heat exchanger 12 as indicated by the flow arrows 19, 21, 22. A controller 60 can be provided to perform the functions of reading and comparing the outputs from the temperature sensors 52, 54, and of outputting a pump signal to start the pump 56 to circulate the heat transfer fluid through the interior solar energy collecting heat exchanger 12 when the roof temperature exceeds the temperature of the heat storage medium 30 by some predetermined amount. The controller 60 can also be programmed to prevent the pump 56 from circulating heat transfer fluid through the interior solar energy collecting heat exchanger 12 and into the heat storage tank 18 if desired, for example, when the heat storage medium temperature sensor 54 senses a temperature of the heat storage medium 30 that has reached or is higher than some predetermined maximum temperature for the heat storage medium. For example, but not for limitation, it might be desired to limit the temperature of the heat storage medium 30 to a temperature that will not burn or scald a person's skin in systems in which the heat storage medium is used to either provide or heat water for showers, hot water faucets, and the like. The signal connections 62, 64, 66 between the controller 60 and the respective roof temperature sensor 52, heat storage medium temperature sensor 54, and pump 56 can be hard wired or any other signal transmitting medium, including, but not limited to, light, infrared, radio frequency, sonic or sub-sonic, and either digital or analog, as would be understood by persons skilled in the art once they understand the principles of this invention.

An optional heat disposal subsystem 100 can also be provided, as illustrated for example in FIG. 1, comprising an uninsulated heat disposal tank 102 that is positioned on a basement floor F or in contact with bare ground G under or adjacent to the building or even in contact with ground water under or adjacent to the building B for use as a heat sink. A primary purpose for the heat disposal subsystem 100 may be to drain excess heat from the attic A or other interior space I in which the solar energy collecting heat exchanger 12 is located during periods of high intensity solar radiation, when the heat storage medium 30 in the heat storage tank 18 has already reached a desired maximum temperature. For example, by circulating a heat transfer fluid through the interior solar energy collecting heat exchanger 12 and the heat disposal tank 102, as indicated by the flow arrows 20, 21, 22, 24, 26, 29 in FIG. 1, heat from the roof R and attic A of the building B is absorbed and transferred by the heat transfer fluid to a heat disposal fluid 104 in the heat disposal tank 102. Heat that is drawn away from the roof R and attic A in this manner to the heat disposal fluid 104 in the basement of the building B does not heat up the main living or working spaces in the building B as much as it would if it was left to build up in the attic A. Over time, including during nights and other periods when solar radiation is low, the heat in the heat disposal fluid 104 in the heat disposal tank 102 can dissipate into the basement floor F or into the ground G, which is generally cooler than a building roof R during summers and other times of the seasons when roof R temperatures reach high enough temperatures. Optionally, cooled heat disposal fluid 104 can be used to feed or supplement a building cooling system (not shown), to prevent surfaces such as roofs, sidewalks, driveways, and the like from freezing during certain climatic conditions, or to provide a fluid source for a ground source heat pump system, any or all of which are represented symbolically in FIG. 1 by the feed flow arrow 110 and return flow arrow 112. Persons skilled in the art would be able to implement such heat dissipation from such heat disposal fluid 104 flows 110, 112 into such surfaces or to use such heat disposal fluid 104 flows 110, 112 in heat pump system applications for heating or cooling interior spaces in the building once they read this description in conjunction with the drawings.

The heat disposal fluid 104 can be the heat transfer fluid for transferring the heat from the interior solar energy heat exchanger assembly 12 to the heat disposal tank 102 by circulating the heat disposal fluid 104 directly from the heat disposal tank 102 through the interior solar energy heat exchanger assembly 12 with the heat transfer fluid pump 56 as indicated by the flow arrows 20, 21, 22, 24, 26, 29 in FIG. 1. Alternatively, the heat transfer fluid from the heat disposal fluid return pipe 126 can be flowed through a heat disposal fluid heat exchanger 128 illustrated in phantom lines in FIG. 1, where the heat in the heat transfer fluid can be transferred to the heat disposal fluid 104 in the heat disposal tank 102.

The heat transfer fluid can be water, a water solution, or any liquid that is compatible with the system, e.g., not caustic so that it does not damage pipes and other components, reasonably high vapor pressure so that it does not evaporate too quickly, etc., as would be understood by persons skilled in the art. If water is used for the heat transfer fluid, it may be desirable in some applications to include an anti-freeze ingredient or other solute in solution with the water to either lower the freezing temperature of the solution to some temperature below the freezing temperature of water or to raise the boiling temperature of the solution to some temperature above the boiling point of water. Such solutes are well-known to persons skilled in the art and are available commercially with instructions that are easily understandable to persons skilled in the art. Also, all of the pipes that carry the heat transfer fluid in the system may be sloped to drain the heat transfer fluid to the insulated tank 18 or to the uninsulated heat disposal tank 102 or both.

An example interior solar energy heat exchanger assembly 12 illustrated in FIGS. 2 and 3 comprises at least one heat-conductive panel 14 that is sized and configured for mounting in heat conductive relation to the interior surface S of the roof R so that heat from solar energy absorbed by the roof R can be conducted directly from the roof R materials into the interior heat exchanger assembly 12. An example typical roof R structure illustrated in FIG. 3 may comprise some type of roof sheathing P (e.g., plywood, composite sheet board material, or other materials) mounted on and supported by a plurality of roof rafters or trusses T, some kind of waterproof underlayment material U (e.g., asphalt impregnated felt, tar paper, or similar product) laid on the sheathing, and a matrix of shingles Z covering the underlayment material, all of which provides a weatherproof roof R structure. Alternative roof R structures are myriad, some of which may comprise metal roofing sheets (not shown) mounted on the sheathing S instead of the underlayment U and shingles Z or simply mounted directly on the rafters or trusses T. The heat conductive panel 14 of the example interior solar energy heat exchanger assembly 12 in FIGS. 2 and 3 can comprise a sheet 130 of material that has high thermal conductivity and that is sized and shaped to fit between the rafters or trusses T for fastening to the interior surface S of the roof R between the rafters or trusses T (or to fit between the studs (not shown) of exterior walls if wall mounting is desired). High thermal conductivity is defined for purposes of this description as at least 1 watt per meter kelvin (W/(m·K)), and heat insulating is defined for purposes of this description as less than 1 watt per meter kelvin (W/(m·K)). At least one tube 132 is formed into or fastened onto the sheet 130 of each panel 14 for conducting the heat transfer fluid in heat conducting relation to the sheet 130. For example, the tubes 132 may be welded to the sheets 130, or they may be adhered, fastened with brackets (not shown) or any other convenient fastening method or instrumentality that provides good heat conduction between the sheets 130 and the tubes 132. Any convenient fasteners 134, e.g., screws, nails, adhesive, or other fasteners, can be used to fasten the panels 14 to the interior surface S of the sheathing P or other roofing structure that might be used for a particular roof R. The tubes 132 can extend straight from one end of the panel 14 to the other, as shown for example in FIGS. 2 and 3, or they could be curved, zigzag, or any other pattern that provides more tube-to-sheet contact length per length of sheet 130. A top header pipe 136 and a bottom header pipe 138 are provided to gang a plurality of panels 14 together. In use, solar energy absorbed by the roof R from incident solar radiation is transmitted by conduction and some infrared radiation as well as some convection in the attic A of the building to the sheets 130 of the panels 14. The heat transfer fluid is distributed by the top header 136 to the individual tubes 132 of each panel 14. The heat is transferred primarily by conduction from the sheets 130 and tubes 132 to the heat transfer fluid that flows through the tubes 132. The heat transfer fluid from each panel 14 is gathered by the bottom header 138 and conducted to the heat storage medium 30 in FIG. 1 or to the heat disposal fluid 104 in FIG. 1 as explained above.

An example operation of the interior solar energy collection system in FIG. 1 is illustrated by the logic flow diagram in FIG. 4. Such operation can be implemented with one or more microprocessors, computers, or other digital or analog controller, as represented by the controller 60 in FIG. 1. Such implementation can be accomplished by persons skilled in the art once they understand the principles of the invention.

In the example operation illustrated in FIG. 4, DIFFTEMP is a variable that represents a minimum difference between a temperature of the roof R and a fluid to be heated, for example, the heat storage medium 30 in the insulated tank 18 or the heat disposal fluid 104 in the uninsulated heat disposal tank 102. A value for DIFFTEMP can be an arbitrary value, for example, a value that is targeted to be sufficient to justify activating the heat transfer fluid pump 56 or that provides a sufficient delay in activating the heat transfer fluid pump 56 to avoid excessive cycling of the heat transfer fluid pump 56 on and off. For example, but not for limitation, a DIFFTEMP in a range of about 5 to 20 degrees Fahrenheit (about 3 to 11 degrees Celsius) is a practical value for these purposes. MAXTEMP_(STORAGE) is a variable that represents a maximum temperature for the heat storage medium 30 desired by a user. For example, but not for limitation, it may be desired to not let the temperature of the heat storage medium to exceed a safe hot water temperature, such as some value in a range of about 120 to 140 degrees Fahrenheit (about 50 to 65 degrees Celsius). MAXTEMP_(DISPOSAL) is a variable that represents a maximum temperature for the heat disposal fluid 104 desired by a user. For example, but not for limitation, MAXTEMP_(DISPOSAL) could be the same or similar to the MAXTEMP_(STORAGE) value for the same or similar reasons, or it may be desirable to set MAXTEMP_(DISPOSAL) at a somewhat higher temperature so that the heat disposal subsystem 100 continues to operate to remove heat from the roof R and attic A, even after the heat storage medium 30 reaches the desired MAXTEMP_(STORAGE) value. The values for DIFFTEMP, MAXTEMP_(STORAGE), and MAXTEMP_(DISPOSAL) can be stored in a memory, which may be part of, or connected to, the controller 60, or they can be input by an operator, for example, with or without a prompt.

In the example operation illustrated in FIG. 4, the variable TEMP_(ROOF[52]) represents the temperature of the roof R as sensed by the roof temperature sensor 52. TEMP_(STORAGE[54]) represents the temperature of the heat storage medium 30 as sensed by the heat storage medium temperature sensor 54. TEMP_(DISPOSAL[116]) represents the temperature of the heat storage medium 30 in the heat storage tank 18. TEMP_(OURSIDE[114]) represents the ambient temperature of the atmosphere outside of the building B.

The example operation illustrated in FIG. 4 begins at a start step 170, whereupon the values for DIFFTEMP, MAXTEMP_(STORAGE), and MAXTEMP_(DISPOSAL) are input or retrieved from memory at steps 172, 174, 176, respectively. Then, at steps 178, 180, 182, the temperatures from the roof temperature sensor 52 (TEMP_(ROOF[52])), the heat storage medium temperature sensor 54 (TEMP_(STORAGE[54])), and the disposal fluid temperature sensor 116 (TEMP_(DISPOSAL[116]), respectively, are read or acquired. With that information, the DIFFTEMP is added to the temperature of the heat storage medium 54 (TEMP_(STORAGE[54])) and the resulting sum is compared to the roof temperature 52 (TEMP_(ROOF[52])) at step 184. If that sum is less than the roof temperature 52 (TEMP_(ROOF[52])) at step 184, then the temperature of the heat storage medium 30 (TEMP_(STORAGE[54])) is compared to the maximum desired temperature for the heat storage medium 30 (MAXTEMP_(STORAGE)) at step 186. If the temperature of the heat storage medium 30 (TEMP_(STORAGE[54])) at step 186 is less than the maximum desired temperature for the heat storage medium 30 (MAXTEMP_(STORAGE)), then the primary heat transfer fluid pump inlet valve 140 (VALVE₁₄₀) and the primary heat transfer fluid return valve 142 (VALVE₁₄₂) are opened at step 188, the secondary heat transfer fluid pump inlet valve 144 (VALVE₁₄₄) and the secondary heat transfer fluid return valve 146 (VALVE₁₄₆) are closed at step 190, and the heat transfer fluid pump 56 (PUMP₅₆) is activated at step 192.

However, if either the sum of DIFFTEMP plus the temperature of the heat storage medium 54 (TEMP_(STORAGE[54])) is not less than the roof temperature 52 (TEMP_(ROOF[52])) at step 184 or the temperature of the heat storage medium 54 (TEMP_(STORAGE[54])) is not less than the maximum desired heat storage medium temperature (MAXTEMP_(STORAGE)) at step 186, then DIFFTEMP is added to the temperature of the heat disposal fluid temperature 116 (TEMP_(DISPOSAL[116])) and the resulting sum is compared to the roof temperature 52 (TEMP_(ROOF[52])) at step 194. If that sum is less than the roof temperature 52 (TEMP_(ROOF[52])) at step 194, then the heat disposal fluid temperature 116 (TEMP_(DISPOSAL[116])) is compared to the maximum desired temperature for the heat disposal fluid 104 (MAXTEMP_(DISPOSAL)) at step 196. If the heat disposal fluid temperature 116 (TEMP_(DISPOSAL[116])) is less than the maximum desired temperature for the disposal fluid 104 (MAXTEMP_(DISPOSAL)) at step 196, then the secondary heat transfer fluid pump inlet valve 144 (VALVE₁₄₄) and the secondary heat transfer fluid return valve 146 (VALVE₁₄₆) are opened at step 198, the primary heat transfer fluid pump inlet valve 140 (VALVE₁₄₀) and the primary heat transfer fluid return valve 142 (VALVE₁₄₂) are closed at step 200, and the heat transfer fluid pump 56 (PUMP₅₆) is activated at step 192.

However, if either the sum of DIFFTEMP and the heat disposal fluid temperature 116 (TEMP_(DISPOSAL[116])) is not less than the roof temperature 52 (TEMP_(ROOF[52])) at step 194 or the heat disposal fluid temperature 116 (TEMP_(DISPOSAL[116])) is not less than the maximum desired temperature for the disposal fluid 104 (MAXTEMP_(DISPOSAL)) at step 196, then the heat transfer fluid pump 56 (PUMP₅₆) is deactivated at step 202, and the primary heat transfer fluid pump inlet valve 140 (VALVE₁₄₀), the primary heat transfer fluid return valve 142 (VALVE₁₄₂), the secondary heat transfer fluid pump inlet valve 144 (VALVE₁₄₄), and the secondary heat transfer fluid return valve 146 (VALVE₁₄₆) are all opened at step 204 to allow heat transfer fluid in the pipes to drain down and into the heat storage tank 18 or into the heat disposal tank 102 or both, especially if the heat transfer fluid is the same fluid as the heat storage medium 30 and the heat disposal fluid 104. In other words, if either the sum of DIFFTEMP and the heat disposal fluid temperature 116 (TEMP_(DISPOSAL[116])) is not less than the roof temperature 52 (TEMP_(ROOF[52])) at step 194 or the heat disposal fluid temperature 116 (TEMP_(DISPOSAL[116])) is not less than the maximum desired temperature for the disposal fluid 104 (MAXTEMP_(DISPOSAL)) at step 196, then the solar energy collection process is essentially shut down until either of those two conditions no longer exists.

After both of the steps 192 and 204, the logic returns to re-read the temperatures TEMP_(ROOF[52]), TEMP_(STORAGE[54]), TEMP_(DISPOSAL[116]), and TEMP_(OUTSIDE[114]) at steps 178, 180, 182, respectively, and then cycles through the logic again as described above. Of course, manual shut-off or timed shut-off features (not shown in FIG. 4) can also be included and implemented if desired, which would be within the capabilities of persons skilled in the art once they understand the principles of this invention.

Another example interior solar energy heat exchanger 212 for the interior solar energy collection system 10 is illustrated in FIGS. 5 and 6. The example interior solar energy heat exchanger 212 comprises one or more roof panels 214, each of which comprises a sheet 216 of high thermal conductivity material with one or more tubes 218 mounted in thermally conductive contact with the sheet 216. For example, the tubes 218 can be mounted to the sheets 216 with brackets 220, which protrude from the interior surfaces 222 of the respective sheets 216, as illustrated in FIG. 6. In FIG. 6, the brackets 220 are shown with the bracket 220 material in extending in heat conductive contact with the tubes 218 along substantially the entire longitudinal length of the sheets 216, although shorter brackets 218 could be used. The more thermally conductive contact area there is between the bracket 220 and the tube 218, the more efficient the heat conduction between the sheet 216 and the tube 218 will be. The brackets 218 can be formed integrally with the sheets 216, for example by extrusion or other forming process, or they can be fastened by welding, bolts, adhesion, or the like. The tubes 218 are connected in fluid flow relation to the upper header 136 and to the lower header 138 for circulation of heat transfer fluid though the system components as explained above.

In the example interior solar energy heat exchanger 212 illustrated in FIGS. 5 and 6, the sheet 216 of high thermal conductivity material forms the roof R of the building B so that solar radiation can be incident directly on the exterior surface 223 of the sheet 216. The sheets 216 can be metal or another high thermal conductivity material and can be provided with a protective and/or solar radiation absorptive coating (not shown), for example a resin, a composite resin and particulate material mixture, paint, galvanizing, an anti-reflective coating, or other materials that can provide protection for the sheet from oxidation, corrosion, and environmental deterioration or to provide some aesthetic appeal or to enhance solar radiation absorptive characteristics of the sheets 216. Such coating materials are known to persons skilled in the art and readily available commercially. Each high thermal conductivity sheet 216 is wide enough to span one or more rafters or trusses T, which support the sheets 216 as illustrated in FIG. 6. Adjacent sheets 216 are connected together by suitable joints 222 that are shaped, configured, or sealed in a manner that makes them leak proof to water, so that rain does not leak through the roof R. In the example interior solar energy heat exchanger 212 illustrated in FIG. 6, the joint 222 is provided by a longitudinally extending edge portion of the sheet 216 of the heat exchanger panel 214 formed with an upwardly protruding lip 224 and by the adjacent longitudinally extending edge portion of the sheet 216 of the adjacent heat exchanger panel 214 formed with an upwardly protruding ridge 226. The upwardly protruding ridge 226 has an inverted “V” cross-section so that, when the adjacent heat exchanger panels 214 are assembled together as shown in FIG. 6, the longitudinally extending ridge 226 of one heat exchanger panel 214 extends over and caps the longitudinal rib 224 of the adjacent heat exchanger panel 214. Therefore, rain water on the exterior surface of one panel 214 would have to get under the ridge 226 of the adjacent heat exchanger panel 214 and over the rib 224 of the one heat exchanger panel 214 in order to get under the panels to leak into the interior of the building B, which is unlikely in normal weather conditions. A ridge cap 228 (FIG. 5) on the ridge of the roof R can be provided to extend over outer surfaces of the upper edges of the sheets 216, including the joints 222, to prevent water from getting under the sheets 216 or into the ridges 222. Other waterproof joint structures or configurations could also be used. The sheets 216 of the heat exchanger panels 214 are illustrated as flat sheets in FIG. 6, but they can be other configurations, for example, corrugated, convex, concave, or other shapes.

As mentioned above, the interior solar energy heat exchanger assemblies 12, 212 can be used in walls of buildings as well as in the roofs. FIG. 5 shows, for example, a plurality of the heat exchanger panels 214 mounted vertically for a wall W of the building B. The tubes 218 extend vertically in fluid flow relation between an upper header 136′ and a lower header 138′. The headers 136′, 138′ are connected with pipes to circulate the heat transfer fluid as described above for the example interior solar energy collection system 10.

The foregoing description provides examples that illustrate the principles of the invention, which is defined by the features that follow. Since numerous insignificant modifications and changes will readily occur to those skilled in the art once they understand the invention, it is not desired to limit the invention to the exact example constructions and processes shown and described above. Accordingly, resort may be made to all suitable combinations, subcombinations, modifications, and equivalents that fall within the scope of the invention as defined by the claims. The words “comprise,” “comprises,” “comprising,” “include,” “including,” and “includes” when used in this specification, including the features, are intended to specify the presence of stated features, integers, components, or steps, but they do not preclude the presence or addition of one or more other features, integers, components, steps, or groups thereof. 

1. A solar energy collector system for collecting and utilizing energy derived from incident solar radiation on an external surface of a roof of a building that is absorbed by the roof and that is conducted through the roof to an interior surface of the roof, which is supported by a plurality of rafters, or that is radiated from the interior surface of the roof, wherein said solar energy collector apparatus comprises: a plurality of heat exchanger panels, each of which panels comprises at least one tube that has high thermal conductivity and extends in a generally longitudinal direction from a fluid flow connection with an inlet header to a fluid flow connection with an outlet header, and a sheet of material that has high thermal conductivity and that is sized and shaped to fit between the rafters for fastening to the interior surface of the roof between the rafters, wherein the tube is mounted in heat conducting contact with the sheet; a primary heat storage fluid tank; a first primary pipe system extending from the primary heat storage fluid tank to the inlet header and from the outlet header to the primary heat storage fluid tank; and a primary pump in the primary pipe system configured for pumping fluid from the primary heat storage fluid tank to the inlet header.
 2. The solar energy collector system of claim 1, wherein the primary heat storage fluid tank is heat insulated and sized and shaped for location in the building.
 3. The solar energy collector system of claim 2 including: a heat disposal fluid storage tank that is not heat insulated and that is sized and shaped for location in the building in heat conductive relation with a foundation of the building or with ground under or adjacent to the building; a secondary pipe system extending from the heat disposal fluid storage tank to the inlet header; and a secondary pump in the secondary pipe system configured for pumping fluid from the heat disposal fluid storage tank to the inlet header and from the outlet header to the heat disposal fluid tank.
 4. The solar energy collector system of claim 3 including a utility heat exchanger in the primary heat storage fluid tank adapted for connection to a domestic water supply that serves the building and to a domestic water heater that supplies hot water to hot water furnishings in the building, wherein the utility heat exchanger conducts heat from a heat storage fluid in the primary heat storage fluid tank to domestic water from the domestic water supply before such domestic water flows to the hot water heater.
 5. The solar energy collector system of claim 4, including a supplemental heater in the primary heat storage fluid tank for providing additional heat to the heat storage fluid in the primary heat storage fluid tank.
 6. The solar energy collector system of claim 5, including a control system comprising: a roof temperature sensor positioned adjacent to the interior surface of the roof for detecting temperature at the interior surface of the roof; a primary heat storage fluid temperature sensor positioned in the primary heat storage fluid tank for sensing temperature of the heat storage fluid in the primary heat storage fluid tank; a controller that is programmed to receive signals from the roof temperature sensor and from the primary heat storage fluid temperature sensor and to output a signal to turn on the primary heat storage fluid pump to pump fluid from the primary heat storage fluid tank to the inlet header when the temperature at the interior surface of the roof is greater than the temperature of the heat storage fluid in the primary heat storage fluid tank.
 7. The solar energy collector system of claim 6, wherein the secondary pipe system is connected and integrated in fluid flow relation with the primary pipe system such that the primary heat transfer fluid pump is also the secondary pump for pumping fluid from either the primary heat storage fluid tank or the heat disposal fluid tank or both to the inlet header.
 8. The solar energy collector system of claim 7, including a building heating system that is configured to draw heated fluid from the primary heat storage fluid tank for transfer to and heating of an interior environment in the building.
 9. The solar energy collector system of claim 8, including a building cooling system that is configured to draw cold fluid from the secondary fluid storage tank for transfer to and cooling of the interior environment of the building.
 10. The solar energy collector system of claim 8, including a heat dissipation system that is configured to dissipate heat from the heat disposal fluid to surfaces or interior spaces that are desired to be heated.
 11. The solar energy collector system of claim 8, including a ground source heat pump system that utilizes the heat disposal fluid as a source of heat or as a heat sink to dispose of heat.
 12. A method of collecting heat from solar energy that is incident on a roof or exterior wall of building, comprising: circulating a heat transfer fluid through a tube that is connected in thermally conductive contact with an interior surface of a sheet that is in thermally conductive contact with, or that forms a part of, the roof or exterior wall of the building so that heat in the sheet transfers by conduction into the heat transfer fluid; and circulating the heat transfer fluid through a heat storage tank in the building.
 13. The method of claim 12, including: comparing a temperature of the roof or exterior wall with a temperature of a fluid in the heat storage tank: and circulating the heat transfer fluid through the heat storage tank only when the temperature of the roof or exterior wall is higher than the temperature of the fluid in the heat storage tank.
 14. The method of claim 13, including circulating the heat transfer fluid through the heat storage tank only when the temperature of the roof or exterior wall is higher than the temperature of the fluid in the heat storage tank and the temperature of the fluid in the heat storage tank is less than a predetermined desired maximum temperature.
 15. The method of claim 14, including circulating the heat transfer fluid through a heat disposal tank when the temperature of the roof or exterior wall is higher than the temperature of the fluid in the heat storage tank and the temperature of the fluid in the heat storage tank is higher than the predetermined desired maximum temperature. 